1. Field of Invention
The present invention relates to an external device extension method and an external device for various kinds of hosts, and more particularly to an external device extension method and an external device for computers and smart appliances.
2. Description of Related Arts
A host is connected to an external device for extending its applications.
A host like a computer system can employ numerous external devices. A conventional external device extension method is generally achieved by using the universal interfaces of the host and installing specified applications and drivers on the host.
This method is convenient and effective when the host incorporates a combination of Window operating system and Intel processor. However, because the number of the versions of the operating systems is growing more and more, and the driver package is getting larger and larger, its use and maintenance becomes more and more difficult. Many external devices have to select to support one or several limited number of versions, so that these external devices cannot be used on the older hosts, and even are not usable on the newer hosts.
Much effort has been expended in facilitating improved use of external devices.
Microsoft Corporation has defined four types of USB devices that do not require installing additional drivers under the operating system of Windows XP SP2 and the operating systems thereafter, those USB devices are classified into four following types.
1. USB Video Class (UVC), which mainly refers to cameral like products.
2. USB Audio Class (UAC), which mainly refers to USB sound cards.
3. USB Human Interface Device, which mainly refers to mouse and keyboards of USB interface, and the like.
4. USB Mass Storage Device, which main refers to USB flash drives.
An agreement has been made that each type of above devices is designed to comply with a predetermined specification, a universal driver associated with the predetermined specification is developed and integrated into the operating system. The universal drivers enable the normal operations of an external device, as long as the external device complies with the predetermined specification. This has significantly brought down the difficulties for the users of the Windows operating system.
With the development of computer science, the situation of the only combination of Windows operating system and Intel processor has changed. The use of Linux operating systems and other embedded operating systems, ARM and MIPS based processors has become popular. The current external device extension methods and external devices cannot meet these requirements.
Although, smart appliances like hosts, such as cell phones, TV sets, Mobile Internet Devices, Pictorial Navigation Displays, media players, webcams, digital cameras, digital videos, and netbooks, with MIPS or ARM processors have a larger computing capability than the conventional computers and also support some universal interfaces, unlike the computers, they cannot use and connect to a plurality of external devices according to the current external device extension methods. One reason is that some hosts don't use the specific combination of Windows operating system and Intel processor. In addition, it is hard to find a suitable version driver, as there are many types of hosts. Another reason is that some hosts use embedded software, so that the installation and uninstallation of drivers and applications can only be achieved by upgrading the equipment of the hosts. The performance of the host which can be installed drivers may become poor because of the installation and uninstallation of the driver, so that the use of external devices is limited. Simultaneously, the resources such as the memory and interfaces of these hosts are relatively limited, so that it is impossible for pre-integrating various drivers and applications to the host.
In view of the above, the current external device extension methods and external devices cannot accommodate the situation of diversifying hosts and external devices, the hosts of a combination other than Windows operating system and Intel processors, and situations which require great computing ability and can only support U-disks, micro SD cards, SD cards or the internet, or transfer files through Bluetooth, IR, or WIFI under FTP and OBEX protocols, but cannot use other external devices.